Security features within the meaning of the present application are feature substances, which are incorporated in and/or applied to the document of value e.g. in the form of pigments. A pertinent checking system is known for example from WO 97/39428. This document teaches, that a bank note shall contain a high-security feature, incorporated in or applied to the paper, consisting of a mixture of two different substances and a low-security feature consisting of another substance. In a high-security area, such as e.g. a bank, the high-security feature is checked, whereas in a low-security area, such as e.g. in publicly accessible vending machines, only the low-security feature is checked.
By incorporating different security features with different characteristic properties into bank notes, a simple checking of the low-security feature is enabled in areas without high demands on security, such as e.g. in the trade, while the high-security feature is checked only in high-security areas, i.e. e.g. by users with a higher security category.
Such an incorporation of different feature substances for different security categories, however, increases the effort required for a suitable selection of appropriate feature substances and thus for the production of the pertinent documents of value.